Casing scraper



Feb. 23, 1954 z ci-l 2,670,046

CASING SCRAPER Filed Jan. 5, 1950 Z I 1 I5 i l2a l j. 7' l 19 7INVENTOR: Haber! B. Km bach ATTORN E Y Patented Feb. 23, 1954 UNITEDSTATES PATENT OFFICEJ CASING SCRAPER Robert B. Kinzbach, Houston, Tex.Application January 3, 1950, Serial No. 136,449

1 This invention relates to a casing scraper.

An object of the invention is to provide a tool of the characterdescribed for smoothing and conditioning the inside of a casing, orother pipe, set in a well bore.

In carrying on operations in a Well, the interior of the casing shouldbe kept as smooth and as nearly round as possible so as not to interferewith said operations nor to injure the tools or equipment by means ofwhich the operations are carried on; for example, well casing is oftenperforated opposite potentially productive strata by what is commonlyknown as a well shooting gun, and if no oil is produced therefrom theperforations are cemented up by filling the casing with cement oppositesaid perforations and allowing it to set around and within the casing.Thereafter, the cement is often drilled out of the casing in order tocarry on operations beneath, and the casing should be smoothed,interiorly, in order to condition it for the carrying on of suchoperations through it.

It is the object of the present invention to provide a casing scraperwhich can be incorporated into the drill stem adjacent the drill and bymeans of which the casing may be scraped, smoothed and conditionedsimultaneously with the drilling out process.

Another object is to provide a tool of the character described whichwill remove inwardly extending projections from the pipe such as burrsor bullets or the like.

Of course, the tool may be used in tubular ob jects anywhere for thepurpose indicated.

Other objects and advantages will be apparent from the followingspecification, which is illustrated by the accompanying drawings,wherein:

Figure l is a side elevation of the tool, partly in section, shownconnected into a drill stem and associated with a drill used in drillingout the well casing;

Figure 2 is a side elevation, partly in section, of a cutter;

Figure 3 is a cross-sectional view of the scraper taken on the line 3-3of Figure 1;

Figure l is a cross-sectional view taken on the line i l of Figure 1;and

Figure 5 is an enlarged, cross-sectional view taken on the line 5-5 ofFigure 1.

Referring now more particularly to the drawings, wherein like numeralsof reference designate the same parts in each of the figures, thenumeral 5 designates the scraper body, which, in the presentillustration, is of a general cylindrical shape and whose upper end isformed with a reduced, outwardly threaded, tapering pin 2 for theconnection of an operating string 3 to the body. This string 3 mayextend to the ground surface. v

The lower end of the body I may be provided 5 Claims. (01. 166-18) withan internally threaded, downwardly flaredbox 4 to receive the externallythreaded shank of a drill 5.

Of course, the drill may be employed only when the well has becomeobstructed by cement, as 6,-

ly, whose outer ends have the opposing sockets- 9 and ID.

Within the bearing members or housings are the upper and lower yieldableelements ll, l2 which react against the bottom of the respectivebearings and the outer ends of the housings l, 8 so as to independentlyhold said housings yieldably outwardly. These elements may vary inresistance, the stronger elements being so located as to hold thedriving teeth most firmly against the inside wall of the casing.

The upper and lower ends of each cutter Ha are reduced and formed intoextended necks which terminate in ball joints l3, l4 that workindependently in the opposing sockets 9, Ill, as shown in Figure 1.These tapered cutters work in the pockets 6a but project out beyond thesurface of the body so as to contact the inner wall' of the casing wheninserted therein, and the inde-' pendently yieldable housings I and 8cause them' to cant their axes to that of the body until line contact issecured between the periphery of the cutters and the pipe wall to bescraped.

Each cutter includes the driving and scraping" teeth I6, which may behelical, and these teethf required distance apart around may be spacedthe the body, and the the body.

teeth extend longitudinally of The housings l, 8 have side keyways l'l,ll,

which extend out radially, and keys, as l8, are

threaded into the body l at right angles to said keyways and with theirinner, smooth ends projecting into the keyways so as to retain thehousings against detachment, and these keys are locked in place by meansof locknuts 19.

In operation, the body I is rotated, causing a corresponding rotativemovement of the cutters due to the pressure contact between their teeth.

and the pipe wall. Inasmuch as the circumferences of the cutters varyfrom end to end, while that of the pipe it contacts is constant, therotative speed of the cutters will correspond to that of only onediameter (usually the largest because.

of the greater torque at this point) and relative slippage must occurthroughout the balance of the length of the cutter. The magnitude ofthis slippageis controlled by the difference in cutter.-

tapered diameters. This slippage provide the wall scraping action.

Due to independent radial movement of end bearings, the cutters areyieldably forced into line contact with the inner wall or the casing. Inthis position the cutter axis is canted to the body axis by half theincluded angle of the tapered cutter.

As the body is rotated with the cutters in this position, they arecaused to rotate about their axes by the drag of their teeth against thesta tionary wall of the casing.

Since the cutters are conical in shape, their larger diameter end willtend to control their rotative speed to a valve corresponding to thecircumferential casing surface traversed divided by the circumference ofthe cutter at its larger end. Since the circumference of the smaller endf the cutter cannot cover this same circumferential distance in thecasing at this speed relative slippage must occur, starting at zero atthe large diameter end and increasing to a maximum at the small diameterend. By the same reasoning, if the smaller end of the cutter happens tocontrol cutter rotative speed, due to its encountering irregularities ofsuflicient drag to overcome the torque drag at the larger end, thencutter rotative speed will be controlled as a function of this diameter,and slippage will occur to a maximum value at the larger diameter end.

in elTect this design provides a combination of circumferential chippingand sliding action against the casing wall for the removal of burrs,cement coating, and the like.

The housings =7, 8 will break major obstructions in the and the cuttersin rolling will scrape the wall smooth. Each cutter is tapered andfrusto-conical in shapeand has longitudinal teeth spacedabout itsperiphery.

The drawings and description are (illustrative merely, while the broadprinciple of the invent-ion will Ice-defined by the-appended-claims.

What .I claim is:

1-. A tool of the character described comprising, a body, rollingcutters, end bearings mounted on the body for supporting said cutters,at their -op-.

posite ends for independent angular movement relative to the bearingsand independent radial movement relative to said body, and yieldablemeans cooperable with said bearings and body to yielding-1y .hold saidbearings outwardly with respect to the body, said bearings also shapedto form bumpers for the removal of major obstructions ahead of rollercontact.

2. A tool of the character described comprising a body adapted to beconnected to an operating string for rotation with the string and havingoutwardly opening pockets therein, outwardly opening aligned recessesabove and below each of 'saidpockets, a bearing member in each 'of'saidrecesses extending outwardly beyond the body and movable inwardly andoutwardly thereof, a frusto-conical rolling cutter rotatably mounted atits opposite ends between the bearing-members o'f each of the pockets'for independent angular movement relative thereto, resilient-means inthe recesses :in engagement with the body and :said heating members and:urging said :members routwardly of said recesses and stop means on thebody engageable with said "bearing members to limit outward movement ofthe bearing members.

3. 'A-toolior the character described comprising a cy-lindrically shapedbody adapted to be conneoted at one end to'an operating string forrota-- tion with the string, said body having z-p'erinher-a 4ally-spaced, vertically-elongated outwardly-opening pockets therein andan outwardly-opening radially-extending bearing recess beyond each endof each of said pockets and in alignment therewith, a bearing memberpositioned'in each of said recesses and extending outwardly thereof,said bearing members being movable inwardly and outwardly of therecesses, a rolling cutter rotatably mounted at its opposite ends in thebearing members of each pocket for independent angular movement relativethereto, and resilient means in said recesses between said body and saidbearing members and cooperable with the body and said members to urgesaid members outwardly of the recesses.

4. A tool of the character described comprising a cylindrically shapedbody adapted to be connected at one end to an operative string to retatewith the operating string said body having radially-disposedvertically-elongated outwardlyopenin-g pockets therein, and aradially-extending outwardly-opening bearing recess above and beneatheach of said pockets and aligned therewith, a bearing member positionedineaeh of said recesses and substantially closing the same, said bearingmembers extending outwardly beyond the body and being independentlymovable inwardly and outwardly of the recesses, a rolling cutterpositioned between and .rotatably mounted at its opposite ends in thebearing member o-f each pocket for independent angular movement relativethereto, resilient means in said recesses, engageable with said body andsaid bearing membars to .yieldingly resist movement of said membersinwardly 'oi said recesses, and-stopmeans on the body engageable with.said members to limit outward movement of said members in .saidrecesses.

5. A tool of the character described comprising a eylindricallyshaped'body adapted to be connectedat one end toan operating stringfor-rotation with the string and having outwardly-openingvertically-elongated, pockets therein, and aligned,outwardly-openi-ng.bearing recesses .beyond the ends of each of thepockets, a bearing member positioned in each recess for movementinwardly and outwardly thereof and extending outwardly beyond the body,a frusto-conical rolling cutter rotatably mounted-rat its opposite endsin the bearing members of each pocket .for independent angular movementrelative thereto, resilient imeans positioned irl said recesses andengage-able with :said body and said bearing members to urge saidcutters away from said body, and stop meanson the body engageable withthe bearing members to limit outward movement of the members.

ROBERT B. KINZBAGH.

References Cited in 'thefiile o'fth'is patent srAr-Es PATENTS 179,850Germany .1907

